Catheter with stepped skived hypotube

ABSTRACT

Catheter having a hypotube with a skive defined by a first angled cut, an axial cut, and a second angled cut. A midshaft member includes a guidewire lumen and an inflation lumen in fluid communication with an inflation lumen of the hypotube, the inflation lumen of the midshaft member configured to receive at least a portion of the hypotube. A distal tubular shaft member extends distally from the midshaft member. The distal tubular shaft member has a guidewire lumen and an inflation lumen defined therein, the guidewire lumen of the distal tubular shaft member in fluid communication with the guidewire lumen of the midshaft member. The inflation lumen of the distal tubular shaft member is in fluid communication with the inflation lumen of the midshaft member and a balloon is coupled to the distal tubular shaft member and in fluid communication with the inflation lumen.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. patent application Ser. No.14/458,327, filed Aug. 13, 2014, which is a continuation of U.S. patentapplication Ser. No. 13/481,441, filed May 25, 2012, now U.S. Pat. No.8,834,510 issued Sep. 16, 2014, which claims the benefit of U.S.Provisional Patent Application Ser. No. 61/490,547, entitled “CatheterWith Stepped Skived Hypotube” and filed on May 26, 2011, the entirecontent of each of which is incorporated herein by reference.

BACKGROUND OF THE DISCLOSED SUBJECT MATTER Field of the DisclosedSubject Matter

The disclosed subject matter herein generally relates to medicaldevices, and particularly to intracorporeal devices for therapeutic ordiagnostic uses, such as balloon catheters.

DESCRIPTION OF RELATED SUBJECT MATTER

In percutaneous transluminal coronary angioplasty (PTCA) procedures, aguiding catheter is advanced in the vasculature of a patient until thedistal tip of the guiding catheter is seated in a desired coronaryartery. A guidewire is advanced out of the distal end of the guidingcatheter into the coronary artery until the distal end of the guidewirecrosses a lesion to be dilated. A dilatation catheter, having aninflatable balloon on the distal portion thereof, is advanced into thecoronary anatomy over the previously introduced guidewire until theballoon of the dilatation catheter is positioned across the lesion. Oncepositioned, the dilatation balloon is inflated with inflation fluid oneor more times to a predetermined size at a suitable pressure to compressthe stenosis against the arterial wall to open up the vascularpassageway. Generally, the inflated diameter of the balloon isapproximately the same diameter as the native diameter of the body lumenbeing dilated to complete the dilatation but not over expand the arterywall. After the balloon is deflated, blood resumes through the dilatedartery and the dilatation catheter and the guidewire can be removedtherefrom.

In such angioplasty procedures, there may be restenosis of the artery,i.e. reformation of the arterial blockage, which necessitates eitheranother angioplasty procedure, or some other method of repairing orstrengthening the dilated area. To reduce the restenosis rate and tostrengthen the dilated area, physicians may additionally oralternatively implant an intravascular prosthesis inside the artery atthe site of the lesion. Such stents may be bare metal, polymeric, orcoated with a drug or other therapeutic agent. Stents may also be usedto repair vessels having an intimal flap or dissection or to generallystrengthen a weakened section of a vessel. Stents are usually deliveredto a desired location within a coronary artery in a contracted conditionon a balloon of a catheter which is similar in many respects to aballoon angioplasty catheter, and expanded to a larger diameter byexpansion of the balloon. The balloon is deflated to remove the catheterwith the stent implanted within the artery at the site of the dilatedlesion. Coverings on an inner or an outer surface of the stent have beenused in, for example, the treatment of pseudo-aneurysms and perforatedarteries, and to prevent prolapse of plaque. Similarly, vascular graftscomprising cylindrical tubes made from tissue or synthetic materialssuch as polyester, expanded polytetrafluoroethylene, and DACRON may beimplanted in vessels to strengthen or repair the vessel, or used in ananastomosis procedure to connect vessels segments together. For detailsof example stents, see for example, U.S. Pat. No. 5,507,768 (Lau, etal.) and U.S. Pat. No. 5,458,615 (Klemm, et al.), which are incorporatedherein by reference.

In addition to PTA, PTCA, and atherectomy procedures, balloon cathetersare also used to the peripheral system such as in the veins system orthe like. For instance, a balloon catheter is initially advanced over aguidewire to position the balloon adjacent a stenotic lesion. Once inplace, the balloon is then inflated, and the restriction of the vesselis opened. Likewise, balloon catheters are also used for treatment ofother luminal systems throughout the body.

Typically, balloon catheters comprise a hollow catheter shaft with aballoon secured at a distal end. The interior of the balloon is in afluid flow relation with an inflation lumen extending along a length ofthe shaft. Fluid under pressure can thereby be supplied to the interiorof the balloon through the inflation lumen. To position the balloon atthe stenosed region, the catheter shaft is designed to have suitablepushability (i.e., ability to transmit force along the length of thecatheter), trackability, and flexibility, to be readily advanceablewithin the tortuous anatomy of the vasculature. Conventional ballooncatheters for intravascular procedures, such as angioplasty and stentdelivery, frequently have a relatively stiff proximal shaft section tofacilitate advancement of the catheter within the body lumen and arelatively flexible distal shaft section to facilitate passage throughtortuous anatomy, such as distal coronary and neurological arteries,without damage to the vessel wall.

Traditional catheter shafts are often constructed with inner and outermember tubing separately with an annular space therebetween for ballooninflation. In the design of catheter shafts, it is desirable topredetermine or control characteristics such as strength, stiffness andflexibility of various sections of the catheter shaft to provide thedesired catheter performance. This is conventionally performed bycombining separate lengths of tubular members of different materialand/or dimensions and then assembling the separate members into a singleshaft length. However, the transition between sections of differentstiffness or material can be a cause of undesirable kinking along thelength of the catheter. Such kinking is particularly evident in rapidexchange (RX) catheters, wherein the proximal shaft section does notinclude the additional structure of a guidewire lumen tube. For example,a conventional RX catheter generally consists of a proximal hypotubehaving a single inflation lumen therethrough and a dual lumen or coaxialtube configuration at a distal end section having both a guidewire lumenand an inflation lumen therein. Known techniques to minimize kinking atthe transition between the more rigid proximal section and the moreflexible distal section include bonding two or more segments ofdifferent flexibility together to form the shaft. Such transition bondsneed to be sufficiently strong to withstand the pulling and pushingforces on the shaft during use.

To address the described issues, catheters having varied flexibilityand/or stiffness have been developed with various sections of thecatheter shaft that are specifically tailored to provide the desiredcatheter performance. For example, each of U.S. Pat. No. 4,782,834 toMaguire and U.S. Pat. No. 5,370,655 to Burns discloses a catheter havingsections along its length which are formed from materials having adifferent stiffness; U.S. Pat. No. 4,976,690 to Solar discloses acatheter having an intermediate waist portion which provides increasedflexibility along the catheter shaft; U.S. Pat. No. 5,423,754 toCornelius discloses a catheter having a greater flexibility at itsdistal portion due to both a material and dimensional transition in theshaft; U.S. Pat. No. 5,649,909 to Cornelius discloses a catheter havinga proximal portion with greater stiffness due to the application of apolymeric coating thereto; and U.S. Publication No. 2010/0130925 toHaslinger discloses a multilayer catheter shaft using a combination of ahigh Shore D durometer value material and a lower Shore D durometervalue material to reduce kinking.

However, one difficulty has been balancing the often competingcharacteristics of strength and flexibility of the catheter shaft. Thetransition between sections of different stiffness or material can be acause of undesirable kinking along the length of the catheter. Suchkinking is particularly evident in rapid exchange catheters, wherein theproximal shaft section does not include the additional structure of aguidewire lumen tube. Rather, a conventional rapid exchange cathetergenerally consists at its proximal end section of a covered hypotubehaving a single inflation lumen therethrough and at its distal endsection, a dual lumen or coaxial tube configuration having both aguidewire lumen and an inflation lumen therein. Known techniques tominimize kinking at the transition between the more rigid proximalsection and the more flexible distal section include bonding two or moresegments of different flexibility together to form the shaft. However,such transition bonds need to be sufficiently strong to withstand thepulling and pushing forces on the shaft during use. One difficultly hasbeen providing a flexibility transition which improves cathetermaneuverability, yet with a sufficiently strong transition bond.

Accordingly, there is a need for a catheter having a catheter shaft withan improved combination of characteristics such as strength, flexibilityand ease of manufacture. The disclosed subject matter satisfies theseand other needs.

SUMMARY OF THE DISCLOSED SUBJECT MATTER

The purpose and advantages of the disclosed subject matter will be setforth in and apparent from the description that follows, as well as willbe learned by practice of the disclosed subject matter. Additionaladvantages of the disclosed subject matter will be realized and attainedby the methods and systems particularly pointed out in the writtendescription and claims hereof, as well as from the appended drawings.

To achieve the above and other advantages and in accordance with thepurpose of the disclosed subject matter, as embodied and broadlydescribed, the disclosed subject matter includes, according to oneembodiment, a catheter comprising a hypotube having a proximal sectionand a distal section with an inflation lumen and a longitudinal axisdefined therethrough, the distal section having a skive defined by afirst angled cut, an axial cut, and a second angled cut. The catheterfurther has a midshaft member including a guidewire lumen and aninflation lumen defined therethrough, the inflation lumen of themidshaft member in fluid communication with the inflation lumen of thehypotube. The inflation lumen of the midshaft member is configured toreceive at least a portion of the distal section of the hypotube. Thecatheter further has a distal tubular shaft member extending distallyfrom the midshaft member, the distal tubular shaft member having aguidewire lumen and an inflation lumen defined therein, the guidewirelumen of the distal tubular shaft member in fluid communication with theguidewire lumen of the midshaft member. The inflation lumen of thedistal tubular shaft member is in fluid communication with the inflationlumen of the midshaft member. The catheter further has a balloon coupledto the distal tubular shaft member and in fluid communication with theinflation lumen.

In accordance with another aspect of the disclosed subject matter, thehypotube of the proximal section is free of any outer coating or layer.In this manner, the hypotube can be dimensioned to match thecorresponding outer diameter of a coated hypotube of a conventionalcatheter. Similarly, the inner diameter is increased while maintainingsuitable strength and rigidity. This bare hypotube configuration allowsfor increased rigidity and pushability, as well as increased flow ratesthrough the inflation lumen for inflation and/or deflation as desired,without jeopardizing overall profile. The distal section of the barehypotube is textured, such as by laser treatment, to increase adhesionwith the midshaft section tube.

The distal end of the hypotube can be roughened or textured to improveadhesion of the hypotube with the middle section shaft as describedfurther below. For example, a laser can treat the end of the hypotubefor enhanced adhesion.

A catheter of the disclosed subject matter has an improved transition,such as a flexibility transition along a length of the catheter shaftwhich preferably provides improved trackability. These and otheradvantages of the disclosed subject matter will become more apparentfrom the following detailed description and accompanying exemplarydrawings.

In accordance with another aspect of the disclosed subject matter, amethod of making a catheter is disclosed including providing a hypotubehaving a proximal section and a distal section with an inflation lumenand a longitudinal axis defined therethrough, the distal section havinga skive defined by a first angled cut, an axial cut, and a second angledcut. The method further includes forming a midshaft member including aguidewire lumen and an inflation lumen defined therethrough, theinflation lumen of the midshaft member configured to receive at least aportion of the distal section of the hypotube. The distal section of thehypotube is inserted within the midshaft member with at least the axialcut of the skive engaging the inflation lumen of the midshaft member andthe inflation lumen of the midshaft member in fluid communication withthe inflation lumen of the hypotube. The midshaft member is bonded to anouter surface of the hypotube.

It is to be understood that both the foregoing general description andthe following detailed description are embodiments and are intended toprovide further explanation of the disclosed subject matter claimed. Theaccompanying drawings, which are incorporated in and constitute part ofthis specification, are included to illustrate and provide a furtherunderstanding of the system and method of the disclosed subject matter.Together with the description, the drawings serve to explain theprinciples of the disclosed subject matter.

BRIEF DESCRIPTION OF THE DRAWINGS

The subject matter of the application will be more readily understoodfrom the following detailed description when read in conjunction withthe accompanying drawings, in which:

FIG. 1 is a side view, partially in section, of a balloon catheterembodying features of the disclosed subject matter.

FIG. 2 is a detailed side cross section of the transition region,including the skived distal end of the catheter hypotube disposed withinthe inflation lumen of a midshaft section and extending into a portionof the inflation lumen of the distal shaft member.

FIG. 3A is a detail perspective view of the skive at the distal sectionof the hypotube according to an embodiment of the disclosed subjectmatter.

FIG. 3B is a cross section of the hypotube at section B-B in FIG. 3Aaccording to an embodiment of the disclosed subject matter.

FIGS. 4, 5, 6, 7 are transverse cross sectional schematic views of theballoon catheter shown in FIG. 2, taken along lines 4-4, 5-5, 6-6, and7-7, respectively.

FIGS. 8 and 9 are transverse cross sectional views of the ballooncatheter shown in FIG. 1, taken along lines 8-8 and 9-9, respectively.

FIGS. 10A and 10B are selected images of the cross section of the distalshaft section and the midshaft section according the disclosed subjectmatter.

FIG. 11 illustrates the formation of the catheter shaft outer tubularmember, in which an extruded tube is radially and longitudinallyexpanded in a capture member in a method embodying features of thedisclosed subject matter, with the extruded tube shown prior to beingradially and longitudinally expanded.

FIG. 12 illustrates the extruded tube of FIG. 11 after being radiallyand longitudinally expanded in the capture member.

DETAILED DESCRIPTION

Reference will now be made in detail to embodiments of the disclosedsubject matter, an example of which is illustrated in the accompanyingdrawings. The examples are not intended to limit the scope of thedisclosed subject matter in any manner. The disclosed subject matterwill be described in conjunction with the detailed description of thesystem.

In accordance with an embodiment of the disclosed subject matter, acatheter comprising a hypotube having a proximal section and a distalsection with an inflation lumen and a longitudinal axis definedtherethrough, the distal section having a skive defined by a firstangled cut, an axial cut, and a second angled cut. The catheter furtherhas a midshaft member including a guidewire lumen and an inflation lumendefined therethrough, the inflation lumen of the midshaft member influid communication with the inflation lumen of the hypotube. Theinflation lumen of the midshaft member is configured to receive at leasta portion of the distal section of the hypotube. The catheter furtherhas a distal tubular shaft member extending distally from the midshaftmember is further provided, the distal tubular shaft member having aguidewire lumen and an inflation lumen defined therein, the guidewirelumen of the distal tubular shaft member in fluid communication with theguidewire lumen of the midshaft member. The inflation lumen of thedistal tubular shaft member is in fluid communication with the inflationlumen of the midshaft member. The catheter further has a balloon coupledto the distal tubular shaft member and in fluid communication with theinflation lumen.

In accordance with another aspect of the disclosed subject matter, amethod of making a catheter is disclosed including providing a hypotubehaving a proximal section and a distal section with an inflation lumenand a longitudinal axis defined therethrough, the distal section havinga skive defined by a first angled cut, an axial cut, and a second angledcut. The method further includes forming a midshaft member including aguidewire lumen and an inflation lumen defined therethrough, theinflation lumen of the midshaft member configured to receive at least aportion of the distal section of the hypotube. The distal section of thehypotube is inserted within the midshaft member with at least the axialcut of the skive engaging the inflation lumen of the midshaft member andthe inflation lumen of the midshaft member in fluid communication withthe inflation lumen of the hypotube. The midshaft member is bonded to anouter surface of the hypotube.

For purpose of illustration and not limitation, reference will now bemade in detail to specific embodiments, examples of which areillustrated in the accompanying drawings. For the purposes of thisdisclosure, like reference numbers in the figures shall refer to likefeatures unless otherwise indicated. For purpose of illustration and notlimitation, and unless otherwise noted, reference to dimensions andmaterials of construction will be made to a coronary balloon dilatationcatheter, although it is recognized that alternative dimensions andmaterials of construction can be used for other indications.

Solely for purpose of illustration, an exemplary embodiment of a rapidexchange type balloon dilatation catheter 100 for coronary indicationsembodying features of the disclosed subject matter is shown in FIG. 1.The catheter 100 generally comprises an elongated catheter shaft 110having a proximal shaft portion 120 and a distal shaft portion 130. Thecatheter shaft 110 can have a variety of suitable configurations. Forexample, although depicted as multiple tubes joined together, asdiscussed herein, certain portions can be formed as single monolithicmembers as desired. The shaft 110 has an inflation lumen 200 definedtherein and a guidewire lumen 210 defined through at least a portion ofthe distal shaft section.

In accordance with one aspect of the disclosed subject matter asillustrated in FIG. 1, the proximal shaft section embodied herein is asingle lumen hypotube 220 or similar tubular member of suitable rigidityand pushability. The hypotube 220 is embodied as a single piececonstruction tubular member. The hypotube 220 has a proximal section anda distal section with an inflation lumen 200 and a longitudinal axisdefined therethrough. The inflation lumen 200 of the hypotube cancomprise any suitable configuration, such as a substantially circularconfiguration as embodied in FIG. 1. For purpose of illustration, thesubstantially circular hypotube of FIG. 1 can have a wall thickness ofbetween about 0.0030 inches and about 0.0090 inches when used forcoronary indications. The distal section of the hypotube has a skivedefined by a first angled cut, an axial cut, and a second angled cut, asfurther discussed herein.

In the illustrated embodiment of FIG. 1 and FIG. 2, the hypotube 220 isskived at its distal section with a stepped configuration. The skive isa cut section of the hypotube that gradually reduces in dimension. Thestepped skive improves pushability and resistance to kink by providing asmoother transition between the hypotube and a midshaft member, furtherdiscussed herein.

As depicted in FIG. 2, the skive of the disclosed subject matter hasthree distinct sections comprising a first angled cut 420, an axial cut440, and a second angled cut 460 and the hypotube reduces incross-sectional dimension distally along the skive. The first angled cut420 is at the extreme distal end of the hypotube and the axial cut 440is disposed between the first angled cut 420 and the second angled cut460. The first angled cut 420 extends to a distal end of the hypotube220. For example, the hypotube in the first angled cut 420 can come to apoint at the extreme distal end as depicted in FIG. 2, and in otherembodiments, the distal end of the hypotube includes a blunt end asdepicted in FIG. 3A for purpose of comparison. Other similar steppedconfigurations are contemplated.

The first angled cut 420 and second angled cut 460 each can have alinear or straight angled configuration as depicted herein, or can becurved, such as a parabolic like curve. The first angled cut 420 and thesecond angled cut 460 can have the same angle of inclination or can havedifferent angles of inclination. In one embodiment as depicted in FIG. 2for purposes of illustration, the first angled cut 420 and the secondangled cut 460 are substantially parallel with each other. In anotherembodiment, the first angled cut 420 extends at a first angle relativethe longitudinal axis of the hypotube and the second angled 460 cutextends at a second angle relative the longitudinal axis of the hypotubesuch that the first angle is different from the second angle.

The first angled cut 420, the axial cut 440, and the second angled cut460 can have the same or varying lengths, although the overalldimensions will correspond with dimensions of the midshaft member asdescribed further below. FIGS. 3A and 3B depict a schematic of thedistal section of the hypotube 220 for a coronary balloon dilationcatheter, wherein the hypotube has the first angled cut 420, the axialcut 440, and the second angled cut 460. In the example of FIGS. 3A and3B, the first angled cut 420 has an axial length G between approximatelybetween about 20 mm and about 30 mm. The first angled cut 420 of thisembodiment has a blunt end which can have a distal height H rangingapproximately between approximately 5% to approximately 25% of the outerdiameter of the hypotube 220. In one embodiment, the height H can beapproximately 0.0025 inches to approximately 0.0065 inches.

The axial cut 440 can have an axial length approximately ranging between10 mm and 40 mm. The axial cut 440 can have a height C, as depicted inFIG. 3A, that ranges approximately between about 20% to about 50% of theouter diameter of the hypotube 220. In one embodiment, the height Cranges between about 0.0060 inches and about 0.0110 inches.

FIG. 3B is a cross-section of FIG. 3A along the lines B-B. FIG. 3Bdepicts the outside diameter Ø_(A) and the inside diameter Ø_(B). In oneembodiment, the inside diameter Ø_(B) of the hypotube 220 can beapproximately 0.0200 inches to approximately 0.0220 inches and theoutside diameter Ø_(A) of the hypotube 220 can be approximately 0.0260inches to approximately 0.0280 inches. The second angled cut 460 canhave a height approximately equivalent to the outside diameter of thehypotube 220. Accordingly, in one embodiment, the second angled cut hasan overall height when measured from a side of between about 50% toapproximately 100% of the outer diameter of the hypotube 220. FIG. 3Bfurther depicts the height C of the axial cut 440 in relation to theoutside diameter Ø_(A) and the inside diameter Ø_(B).

Additionally, an end of one or more cuts can be radiused for transitionpurposes. For example, and as depicted in FIG. 3A, a proximal end of thesecond angled cut 460 can comprise a curved or radiused portion. Thesecond angled cut 460 depicted herein includes a radius of approximatelyR 0.040. In the embodiment of FIG. 3A, the overall axial length of theskive with respect to the first section 420, the axial cut 440, and thesecond angled cut 460 can range from approximately 100 mm to 200 mm.Additional dimensions of the skive are contemplated herein and notlimitation.

The catheter 100 further includes a midshaft section. As embodied hereinand as illustrated in FIG. 2, the midshaft section of the catheter 100includes a tubular midshaft member 520. The midshaft member 520 includesa guidewire lumen 210 and an inflation lumen 201 defined therethrough.The inflation lumen 201 of the midshaft member is in fluid communicationwith the inflation lumen 200 of the hypotube 220. Furthermore, at leasta portion of the distal section of the hypotube 220 is disposed withinthe inflation lumen 201 of the midshaft member 520 with the inflationlumen 200 of the hypotube in fluid communication with the inflationlumen 201 of the midshaft member. The inflation lumen 201 of themidshaft member depicted herein comprises a generally crescentconfiguration at a proximal section thereof and the hypotube 220 isinserted into the inflation lumen 201, as further discussed herein.

As embodied herein and as illustrated in FIG. 2, an exterior surface ofthe midshaft member 520 can define a proximal port 280. The proximalport 280 is spaced distally from the proximal end of the catheter 100.The proximal port 280 is configured to receive a guidewire 260therethrough and is in communication with the guidewire lumen 210 of themidshaft member 520. In one embodiment, the proximal port 280 isreinforced by the distal section of the hypotube and the distal sectionof the hypotube is disposed proximate the proximal port of the midshaftmember 520. In another embodiment, at least a portion of the axial cut440 is disposed proximate to the proximal port 280 of the guidewirelumen 210. The location of the proximal port 280 can depend upon variousfactors, such as the size of the balloon, as further discussed herein.

FIG. 4 is a cross-section of the catheter 100 of FIG. 2 along the lines4-4. As depicted in FIG. 4, the hypotube 220 at this section is a singlelumen member defining the inflation lumen 201 therethrough with acircular cross section. FIG. 5 is a cross-section of the catheter 100 ofFIG. 2 along the lines 5-5. In FIG. 5, the inflation lumen 201 of themidshaft member 520 includes a substantially circular cross section. Theinflation lumen 200 of the hypotube 220 is fluidly connected to thelumen 201 of the midshaft member 520. As depicted in FIG. 5, the secondangled cut 460 is disposed within the lumen 201 of the midshaft member520, as further discussed herein.

FIG. 6 is a cross-section of the catheter 100 of FIG. 2 along the lines6-6. The midshaft member 520 at 6-6 includes a crescent like crosssection for the inflation lumen 201. With respect to FIGS. 5 and 6, thelumen 201 of the midshaft member 520 transitions from a circular crosssection at FIG. 5 to a crescent like cross section at FIG. 6. Thetransition of the circular cross section of the midshaft member 520 tothe crescent like cross section of the midshaft member 520 allows for asmooth transition in flow, as described further herein.

At the cross section of FIG. 6, the axial cut 440 is disposed at leastpartially in the crescent inflation lumen 201 and is further discussedbelow. The space above the axial cut 440 defines the volume forinflation fluid flow. The corners of the crescent or “smiley”configuration can be rounded or otherwise provided in a suitable shape.

FIG. 7 is a cross-section of the catheter 100 of FIG. 2 along the lines7-7. FIG. 7 depicts a cross section of the midshaft member 520 in whichthe inflation lumen 201 has transitioned from the crescent configurationto an annular configuration. The first angled cut 420 interfaces withthe midshaft member 520 and is positioned adjacent, below as depicted inFIG. 7, the guidewire lumen 210 as defined by tubular member 240. Theinflation lumen 201 is generally coaxial with the guidewire lumen 210.As depicted FIG. 2, the first angled cut 420 can extend distally beyondthe midshaft member 520 into the distal tubular member 230, as furtherdiscussed herein.

At the cross section of the midshaft member 520 of FIG. 7, inflationlumen 201 and the guidewire lumen 210 each has a circular cross-section.Thus, as embodied herein and as shown in FIGS. 4-7, the inflation lumen200 of the hypotube 220 transitions from a circular cross section atsection 4-4 of FIG. 2, to a generally crescent or “smiley” configurationat section 7-7 of the inflation lumen 201 of the midshaft member 520 andthen ultimately to a dual lumen coaxial arrangement at section 7-7.However, the inflation lumen 201 and the guidewire lumen 210 can have analternative cross-sectional shape as desired.

The skive serves as a male end section of the hypotube 220 and theinflation lumen 200 of the midshaft member 520 serves as the femalereceiving end section. At least a portion of the stepped skive at thedistal end section of the hypotube is configured to be received withinthe inflation lumen 201 of the midshaft member 520. The hypotube 220 isdisposed within the crescent or smiley shaped inflation lumen to fluidlyconnect the inflation lumen 200 of the hypotube with the inflation lumen201 of the midshaft member 520. For example, and as embodied herein theskive portion of the hypotube 220 is disposed within the inflation lumen201 of the midshaft member 520, as depicted in FIGS. 1 and 6. The axialcut 440 interfaces with a portion of a surface of the inflation lumen201 of the midshaft member 520 and at least the axial cut 440 can bepress fit with the inflation lumen 201 of the midshaft member 520. Theaxial cut 440 is likewise partially disposed within the inflation lumen201. Furthermore, as embodied herein, the first angled cut 420 isinserted through the inflation lumen 201 of the midshaft section andinto the distal shaft section, as depicted in FIG. 2 and furtherdiscussed herein. Accordingly, the skive assists in joining andreinforcing the hypotube 220 with the midshaft member 520, whilefacilitating a smooth transition in flexibility.

The hypotube 220 can be bonded along the length of the hypotube or atportions along the length of the hypotube with the midshaft member 520,as depicted in FIG. 2. The distal section of the hypotube can have aroughened outer surface to enhance the bond therebetween. The hypotube220 is concentrically aligned with the midshaft member 520. Accordingly,the outer diameter of the hypotube 220 is sized to fit concentricallywithin the midshaft member 520 at least at a distal section of thehypotube 220.

Furthermore, the hypotube 220 can be bonded with the midshaft member 520along a portion of a length of the hypotube 220. Accordingly, anexterior surface of the hypotube 220 concentrically engages with aninterior surface of the midshaft member 520 in the midshaft section. Theskive couples the hypotube 220 with the midshaft member 520 and isfurther discussed below.

Turning back to FIG. 2, the distal shaft section of the catheter 100further includes a distal tubular shaft member 230 extending distallyfrom the midshaft member 520. The distal tubular shaft member 230 iscoupled the hypotube 220 by the midshaft member 520. The distal tubularshaft member 230 is coupled to the midshaft member 530 by at least oneof bonding, adhesive, lap joint, and butt joint or by other suitableconfigurations as known in the art.

As depicted herein, the distal tubular shaft member 230 has a guidewirelumen 211 and an inflation lumen 202 defined therein. The guidewirelumen 211 of the distal tubular shaft member 230 is in fluidcommunication with the guidewire lumen 210 of the midshaft member 520.The inflation lumen 202 of the distal tubular shaft member 230 is influid communication with the inflation lumen 201 of the midshaft member.

As embodied in FIG. 2, the distal tubular shaft member 230 includes anouter tubular member 231 extending from the midshaft member 520. Theguidewire lumen 211 is defined by tubular member 240 extending from themidshaft member 520 through the outer tubular member 231 of the distaltubular shaft member 230. The outer tubular member 231 and the innertubular member 240 define the inflation lumen 202 of the distal tubularshaft member 230 therebetween in fluid communication with the inflationlumen 201 of the midshaft member 520. Thus, distal tubular shaft member230 can comprise a coaxial annular configuration with the inner tubularmember 240 positioned within the outer tubular member 231.Alternatively, the distal tubular shaft member can be formed as a duallumen monolithic member with the guidewire lumen and the inflation lumendefined therein if preferred.

FIG. 8 is a cross-section of the catheter 100 of FIG. 2 along the lines8-8. As depicted in FIGS. 1 and 8, the inflation lumen 202 of the distaltubular shaft member 230 includes an annular configuration. Theinflation lumen 202 is defined by the annular space between the interiorsurface of the outer tubular member 231 and the exterior surface of theinner tubular member 240, although a variety of suitable shaftconfigurations can alternatively be used including non-coaxial andmulti-lumen extrusions. The transition from the circular to crescent toannular shape of the inflation lumen 200, 201, 202 allows for smoothflow without significant back pressure or resistance.

The inner tubular member 240 defines the guidewire lumen 210, 211configured to slidably receive a guidewire 260 therein. The innertubular member 240 can comprise one tube or be comprised of a pluralityof tubes connected together. The inner tubular member 240 can be thesame member extending through the midshaft member 520, or can be aseparate member connected therein. Such configurations are known. Anexterior surface of the outer tubular member 231 interfaces with aninterior surface of the midshaft member 520 at a distal end section ofthe midshaft member 520. The midshaft member 520 and the outer tubularmember 231 can be coupled in a variety of ways including, but notlimited to bonding, adhesives, lap joints, butt joints and the like. Theinflation lumen 201 of the midshaft member 520 is fluidly coupled to theinflation lumen 202 of the distal tubular shaft member 230 to providefor a path for inflation of the balloon, as further discussed herein.

Thus, from the proximal end section to the distal end section, thecatheter 100 embodied herein transitions from a single lumen (inflationlumen) configuration in the proximal shaft section to a coaxial duallumen (inflation lumen and guidewire lumen) configuration in the distalshaft section. The midshaft section generally defines the juncturebetween the single lumen hypotube and the dual lumen distal shaftsection.

As depicted in FIG. 1, a balloon 140 is coupled to the distal tubularshaft member 230 and is in fluid communication with the inflation lumens200, 201, and 202. FIG. 9 is a cross-section of the catheter 100 of FIG.1 along the lines 9-9. As depicted in FIG. 9, a balloon 140 is sealinglysecured to the distal tubular shaft member 230 such that an interior ofthe balloon is in fluid communication inflation lumens 200, 201, and202.

For example, and turning back to FIG. 1, the balloon 140 has a proximalskirt section bonded to a distal end section of outer tubular member 231and a distal skirt section bonded to a distal end section of innertubular member 240.

Additional features proximate the balloon can include markers, stents,and an atramatic tip (not shown). Examples of such features andadditional features include those described in U.S. Pat. No. 7,862,541;application Ser. No. 12/983,504; U.S. Pat. No. 7,549,975; U.S. patentapplication Ser. No. 12/468,745; U.S. Pat. No. 6,964,750; U.S.application Ser. No. 11/455,382; U.S. Pat. Nos. 7,833,597; 7,322,959;7,303,798; U.S. application Ser. No. 11/775,480; U.S. application Ser.No. 12/945,566; U.S. Publication 2010/0285085; U.S. Publication2010/0189876; and U.S. patent application Ser. No. 11/241,936; thecontents of which are herein incorporated by reference in theirentirety.

As depicted in FIG. 1, an adapter is provided at the proximal end of thecatheter for access to the inflation lumen 200, 201, 202 collectively,and is configured for connecting to an inflation fluid source (notshown). The balloon 140 is provided at a distal end of the catheter andin fluid communication with the inflation lumen 200, 201, 202. Thedistal end of the catheter can be advanced to a desired region of a bodylumen in a conventional manner and balloon 140 inflated to perform amedical procedure, such as dilate a stenosis and/or deliver a stent orthe like. The catheter 100 is then withdrawn or repositioned for anotherprocedure. FIG. 1 illustrates the balloon inflated.

The catheter can comprise a variety of suitable materials. Inparticular, the hypotube can be a more rigid material than the materialof the midshaft member or the distal tubular shaft member. For example,the hypotube is typically a relatively high stiffness material such as ametal, such as but not limited to stainless steel, although a highdurometer polymer can be used. In contrast, the midshaft member coupledto the hypotube can have more flexibility and can comprise a moreflexible material. In one embodiment, the midshaft member comprisesnylon 12 or other suitable polymeric material.

The distal shaft section can be more flexible than the proximal shaftsection. For example, but not limitation, the outer tubular member canbe a single or multi-layer member made of one or more polymers, such asdifferent durometers of polyamide. Similarly, the inner tubular membercan be a single or multi-layer member made of one or more polymericmaterials. For example, in one embodiment, the inner tubular member ismade of a trilayer with PEBAX 72D, Primacore, and HDPE for the outside,intermediary, and inside layers, respectively and discussed furtherherein. The distal shaft section can be distal blown as furtherdiscussed herein. Furthermore, the dual lumen configuration of thedistal tubular shaft member can be constructed by a number of differenttechniques. For example, and as described further below and depictedherein, the combination of the midshaft member and the inner tubularmember of the guidewire lumen can be melted within a shrink wrap, with acrescent shape mandrel therein to define the crescent or “smiley” shapedinflation lumen.

In accordance with another aspect of the disclosed subject matter, thedistal shaft section can be formed of a tubular member or hypotube freeof any outer coating, so as to have a bare exposed outer surface. Inthis manner, a hypotube of larger cross section can be used withoutjeopardizing the profile of the proximal shaft section as compared to aconventional rapid exchange catheter with a coated hypotube. Forexample, the reduction in thickness by omitting a coating can allow fora proportional increase in both the outer diameter and thus the innerdiameter of the tubular member. Thus, the overall profile of thecatheter along the proximal end section can remain the same, but thedimensions of the inflation lumen therein are increased. The increase ininner diameter can result in greater fluid flow for increased inflationor deflation as described. In some embodiments, the flow rate throughthe tubular member can increase the flow rate by 4 times as compared tocatheters with coating having the same overall profile. Further, thebare hypotube can also result in a better grip and a reduction inkinking. When heated to the appropriate temperature, the midshaft membercan be bonded directly to the hypotube. The textured surface at thehypotube can assist the adhesion of the midshaft member to the hypotubeby increasing the surface area at the skive.

As embodied herein, and in accordance with another aspect, the junctureof the midshaft member can be formed as follows. The guidewire lumen canbe formed by connecting an inner tubular member 240 to a tubularmidshaft member at a side opening, which is created in the wall of thetubular midshaft member to define the proximal port 280. The tubularmidshaft member is heated and attached with the inner tubular memberwithin the interior of the midshaft member at the side opening. Amandrel or pressurizing fluid is provided within the guidewire lumenduring the fusion, if desired or needed to maintain the guidewire lumenopen. The crescent inflation lumen of the midshaft member is formedduring the heating process by positioning a crescent shaped mandrelproximate the juncture of the inner tubular member with the tubularmidshaft member. The heating process includes a temperature sufficientto soften or melt the materials of the tubular midshaft member to definethe lumens therein. Shrink wrap material can be used to maintain theouter shape and dimension of the midshaft member by the fusion process.The mandrel and shrink wrap are then removed after the fusion or heatingprocess is complete.

FIGS. 10A and 10B depict images of cross-sections of the midshaftsection during manufacture. FIG. 10A depicts the cross section of themidshaft member 520 and inner tubular member 240 of a coaxialconfiguration, where the guidewire lumen 210 is concentric with theinflation lumen 201, similar to FIG. 8. FIG. 10B depicts a cross-sectionfrom the midshaft member after the melting or fusion process depictingthe inflation lumen defined by a crescent mandrel. The dual lumenconfiguration of FIG. 10B can be formed by a number of other techniques.For example, the midshaft member can further include a dual lumen memberextending at least a length thereof for purpose of strength andtransition from the proximal end section to the distal end section.

In accordance with the disclosed subject matter, at least a portion ofthe catheter shaft 110 can comprise a tubular member formed of abiaxially oriented thermoplastic polymeric material, which in theillustrated embodiment can be the distal tubular shaft member 230(hereafter “the biaxially oriented distal tubular shaft member”) havingthe inflation lumen 202 therein. A catheter of the disclosed subjectmatter can have a biaxially oriented tubular member alternatively oradditionally forming other sections of the catheter shaft including theproximal and midshaft sections. However, unlike the proximal shaftsection, which is typically formed of a relatively-high bendingstiffness material to provide sufficient push (force transmission) foradvancing the catheter in the vasculature, the distal shaft section canhave tubular members with increased flexibility to track over aguidewire in the tortuous vasculature or the like.

The polymeric material of the biaxially oriented distal tubular shaftmember is biaxially oriented by radially and longitudinally expanding anextruded tube used to form the distal tubular shaft member. For example,the biaxially oriented distal tubular shaft member can be formed of arelatively soft/low durometer polymeric material. The polymer can have aShore durometer hardness of not greater than about 55D to about 72D. Avariety of suitable nonporous polymeric materials can be used includingpolyether block amide (PEBAX) copolymers, polyurethanes, polyethylenes,and polyesters. The polymeric material can have various levels ofcrystallinity, and thus can be crystalline or noncrystalline. In anembodiment, the polymer is a single polymer or copolymer (i.e., not ablend of two separate polymers). For example, the polymer can be PEBAX63D, which has a Shore durometer hardness of about 63D.

In one embodiment, the distal tubular shaft member is a single-layeredtubular member formed of the biaxially oriented polymer tubing. However,in other embodiments, the outer tubular member can be a multilayerconfiguration. The multilayer construction can, for example, includedifferent durometers of polyamide. Examples and further disclosure ofbiaxially oriented tubular shaft members are provided in U.S. Pat. No.7,906,066, which is incorporated in its entirety herein.

In the illustrated embodiment of FIG. 1, the biaxially oriented distaltubular shaft member 230 has a uniform outer diameter along the entirelength of the distal tubular shaft member 230. For example, and withreference to a coronary dilation catheter, the biaxially oriented distaltubular shaft member has an inner diameter of about 0.020 to about 0.040inches, and an outer diameter of about 0.0225 to about 0.0435 inchesalong at least a section thereof. The length of the biaxially orienteddistal tubular shaft member 230 herein is between about 10 to about 25cm.

It is desired for the rupture strength of the catheter shaft to begreater than that of the balloon. In the catheter of the disclosedsubject matter, the balloon rated burst pressure is significantly lessthan (e.g., about 4 atm less than, or about 20% less than) that of thebiaxially oriented tubular outer member.

FIGS. 11 and 12 illustrate a method of making a biaxially orientedtubular member such as the biaxially oriented distal tubular shaftmember 230 of the catheter 100 of FIG. 1. A method of the disclosedsubject matter generally comprises melt-extruding a thermoplasticpolymeric material having a relatively low Shore durometer hardness, toform a tube 300 having a lumen 310, a first inner and outer diameter(ID₁, OD₁) and a first length (L₁), and cooling the extruded tube 300 toa temperature (e.g., to room temperature) which is less than an elevatedtemperature of the melt-extrusion. The cooled extruded tube 300 isplaced within a capture member 320, heated to an elevated temperature,and radially and axially expanded in the capture member 320 to a secondinner and outer diameter (ID₂, OD₂) and length (L₂), to therebybiaxially orient the polymeric material of the extruded tube 300. FIG.11 illustrates the extruded tube 300 disposed within the capture member320 prior to being expanded therein, and FIG. 12 illustrates theexpanded tube 300′ within the capture member 320 (i.e., the extrudedtube 300 of FIG. 11 after being radially and longitudinally expandedwithin the capture member 320). After being radially and longitudinallyexpanded, the resulting expanded tube 300′ is cooled to room temperatureand heat stabilized as discussed in more detail below. The catheter issubsequently assembled, at least by sealingly securing a balloon to adistal end of the expanded tubular member such that the balloon has aninterior in fluid communication with the expanded tubular member lumen.

In the embodiment of FIG. 11, the capture member 320 is tubular with aninner surface layer 330 of a lubricious polymeric material such aspolytetrafluoroethylene (PTFE) for subsequent ease of part removal,reinforced with an outer high strength jacket layer 340 such asstainless steel tubing configured to prevent or inhibit diameter creep(growth) after repeated use. Thus, the capture member 320 is configuredto radially restrain the growing tube 300, without the inner or outerdiameter of the capture member 320 increasing at the elevated internalpressures used to radially expand the extruded tube 300.

The extruded tube 300 is heated to the elevated temperature within thecapture member 320, which in the illustrated embodiment comprisesdirecting heat from a heating nozzle 350 at the outer surface of thecapture member 320. In an embodiment, the heating nozzle 350 traversesalong a length of the extruded tube 300, from a first end to theopposite end. Thus, the radial and longitudinal expansion is initiatedwith only the first end of the extruded tube 300 heated by the nozzle350 in one embodiment. In an embodiment, the extruded tube 300 is heatedto an expansion elevated temperature which is less than themelt-extrusion elevated temperature (i.e., less than a meltingtemperature of the polymeric material).

The extruded tube 300 is axially expanded with a load applied on atleast one end of the tube, e.g., using a vertical necking apparatus (notillustrated), and is radially expanded with pressurized media introducedinto the extruded tube lumen from a pressurized media source (notillustrated) connected to one end of the extruded tube 300.Specifically, with the heating nozzle 350 heating the first end of theextruded tube 300, the heating nozzle 350 is moved toward the second endand the load is applied to the second end in the same direction as theheating nozzle movement to axially expand (i.e., stretch lengthwise) theextruded tube 300. The amount of the load required to provide thedesired stretch percent depends on factors such as the tensileelongation, dimensions, material of the tubing 300, pressure of thepressurized media, and the expanded inner diameter. The pressurizedmedia, e.g., compressed air, is at an elevated pressure sufficient toinitiate the radial expansion, such that the wall hoop stress exceedsthe material resistance (typically the yield stress) to stretching atthe blowing temperature. The internal pressure used to radially expandthe tubing 300 is typically about 400 to about 600 psi.

The extruded tube 300 can be simultaneously radially and axiallyexpanded at the elevated temperature, for ease of manufacture. However,it can alternatively be sequentially expanded (i.e., first radially thenlongitudinally, or first longitudinally and then radially).

The tubing 300 can be radially expanded into contact with the innersurface of the capture member 310, to the second outer diameter which isabout equal to the inner diameter of the capture member 310. The tubing300 radially expands in all directions around the tubing circumference,resulting in circumferential orientation of the polymeric material. Inan embodiment, the second inner diameter (ID₂) is at least about 5 timeslarger than the first inner diameter (ID₁) of the extruded tube (i.e.,the blow-up-ratio, BUR, of the expanded tubular member 300′ is at leastabout 5, and is more specifically about 5.8 to about 6). The large BURprovides a high degree of circumferential orientation, for a largeincrease in the rupture pressure of the tubing. In one embodiment, thetubing is radially expanded to substantially the maximum amount possible(i.e., to a BUR which is at least about 80% of the maximum BURpossible). Further embodiments and examples of making a balloon cathetershaft having high strength and flexibility can be found in U.S. Pat. No.7,906,066 entitled “Method of making a balloon catheter shaft havinghigh strength and flexibility,” the contents of which is incorporated byreference herein in its entirety.

Although illustrated as a rapid exchange type balloon dilatationcatheter, it should be understood that a biaxially oriented shafttubular member of the disclosed subject matter can be used in a varietyof catheters and catheter shaft configurations, including stent deliveryballoon catheters and non-rapid exchange type catheters. For example, inone embodiment of an over-the-wire type catheter having a full lengthguidewire lumen which extends from the proximal to the distal end of thecatheter, a biaxially oriented shaft outer tubular member wouldtypically be provided along the distal shaft section (e.g., with aproximal end distally spaced from the proximal end of the catheter and adistal end at the balloon).

In another embodiment, the balloon can be formed of a polymeric materialwhich is compatible with the material forming the outer surface of theshaft, to allow for fusion bonding, although the balloon canalternatively or additionally be adhesively bonded to the shaft. Theballoon can be a relatively high rupture pressure, non-compliantballoon, which in one embodiment has a rupture pressure of about 20 toabout 30 atm, such that the balloon can be inflated in the patientduring a procedure at relatively high working pressure of about 180 atm.In one embodiment, the balloon has a rated burst pressure of about 14 toabout 25 atm. The rated burst pressure (RBP), calculated from theaverage rupture pressure, is the pressure at which 99.9% of the balloonscan be pressurized to without rupturing, with 95% confidence. Generally,a balloon is inflated in the patient during a procedure at workingpressure of about 8 to about 180 atm.

In the embodiment as depicted in FIG. 1, the balloon 140 is depicted asa single layer balloon. However, multilayered balloons are contemplatedherein. An example of a multilayered balloon for a catheter is describedin U.S. Pat. No. 7,828,766 and U.S. application Ser. No. 12/897,202, thecontents of which are herein incorporated by reference in theirentirety. Further, various embodiments of catheters with other balloonconfigurations are described in U.S. Pat. No. 6,923,822; U.S.application Ser. No. 11/189,536; U.S. Publication Nos. 2009/0036829 and2007/0021772, the contents of which are herein incorporated by referencein their entirety.

While the present disclosed subject matter is described herein in termsof certain embodiments, those skilled in the art will recognize thatvarious modifications and improvements may be made to the disclosedsubject matter without departing from the scope thereof. Moreover,although individual features of one embodiment of the disclosed subjectmatter may be discussed herein or shown in the drawings of the oneembodiment and not in other embodiments, it should be apparent thatindividual features of one embodiment may be combined with one or morefeatures of another embodiment or features from a plurality ofembodiments.

It will be understood that the above description of the presentdisclosed subject matter is susceptible to various modifications,changes and adaptations, and the same are intended to be comprehendedwithin the meaning and range of equivalents of the appended claims.

What is claimed is:
 1. A catheter comprising: a hypotube having aproximal section and a distal section with an inflation lumen and alongitudinal axis defined therethrough, the distal section having askive defined by a first angled cut, an axial cut, and a second angledcut, wherein the first angled cut extends at a first angle relative thelongitudinal axis that is not perpendicular thereto, the second angledcut extends at a second angle relative the longitudinal axis that is notperpendicular thereto, and the axial cut is substantially parallel tothe longitudinal axis; a distal shaft portion including a guidewirelumen and an inflation lumen defined therethrough, the inflation lumenof the distal shaft portion in fluid communication with the inflationlumen of the hypotube, the inflation lumen of the distal shaft portionconfigured to receive at least a portion of the distal section of thehypotube; and a balloon coupled to the distal shaft portion and in fluidcommunication with the inflation lumen of the distal shaft portion. 2.The catheter according to claim 1, wherein at least a portion of thedistal section of the hypotube is disposed within the inflation lumen ofthe distal shaft portion, with the inflation lumen of the hypotube influid communication with the inflation lumen of the distal shaftportion.
 3. The catheter according to claim 1, wherein the inflationlumen of the hypotube comprises a substantially circular cross-section.4. The catheter according to claim 1, wherein the hypotube is bondedwith the distal shaft portion along a portion of a length of thehypotube.
 5. The catheter according to claim 4, wherein the distalsection of the hypotube has a roughened outer surface.
 6. The catheteraccording to claim 1, wherein the hypotube is made of a material morerigid than a material of the distal shaft portion.
 7. The catheteraccording to claim 6, wherein the material of the hypotube comprises atleast one of metal or high durometer polymer.
 8. The catheter accordingto claim 1, wherein the hypotube has a wall thickness of between about0.0030 inches and about 0.0090 inches.
 9. The catheter according toclaim 1, wherein the hypotube reduces in cross-sectional dimensiondistally along the skive.
 10. The catheter according to claim 1, whereinthe axial cut is disposed between the first angled cut and the secondangled cut.
 11. The catheter according to claim 1, wherein the firstangled cut and the second angled cut comprise at least one of a linearangled configuration or a curved configuration.
 12. The catheteraccording to claim 1, wherein the first angled cut and the second angledcut are substantially parallel with each other.
 13. The catheteraccording to claim 1, wherein the first angle is different from thesecond angle.
 14. The catheter according to claim 1, wherein at leastthe axial cut interfaces with a portion of a surface of the inflationlumen of the distal shaft portion.
 15. The catheter according to claim1, wherein at least axial cut is press fit with the inflation lumen ofthe distal shaft portion.
 16. The catheter according to claim 1, whereinthe first angled cut has an axial length between approximately 20 mm toapproximately 30 mm.
 17. The catheter according to claim 1, wherein thefirst angled cut has an overall height when measured from a side ofbetween about 5% to approximately 25% of a diameter of the hypotube. 18.The catheter according to claim 1, wherein the axial cut has an overallheight when measured from a side of between about 20% to approximately50% of a diameter of the hypotube.
 19. The catheter according to claim1, wherein the axial cut has an axial length of approximately 10 mm toapproximately 40 mm.
 20. The catheter according to claim 1, wherein thesecond angled cut has an overall height when measured from a side ofbetween about 50% to approximately 100% of a diameter of the hypotube.21. The catheter according to claim 1, wherein a proximal end of thesecond angled cut comprises a radiused portion.
 22. The catheteraccording to claim 1, wherein the skive has an overall axial length ofbetween approximately 100 mm to approximately 200 mm.
 23. The catheteraccording to claim 1, wherein an exterior surface of the distal shaftportion defines a proximal port to receive a guidewire therethrough, theproximal port in communication with the guidewire lumen of the distalshaft portion.
 24. The catheter according to claim 23, wherein thedistal section of the hypotube is disposed proximate the proximal portof the distal shaft portion.
 25. The catheter according to claim 1,wherein the inflation lumen of the distal shaft portion comprises agenerally crescent configuration.
 26. The catheter according to claim 1,wherein the distal shaft portion comprises nylon
 12. 27. The catheteraccording to claim 1, wherein the distal shaft portion comprises: aninner tubular member and having the guidewire lumen of the distal shaftportion defined therein, and an outer tubular member with the innertubular member disposed therein, the outer tubular member and the innertubular member defining an inflation lumen of the distal shaft portiontherebetween.
 28. The catheter according to claim 1, wherein the distalshaft portion comprises at least one of a multilayer construction withdifferent durometers of polyamide or a single-layered tubular memberconstruction.
 29. The catheter according to claim 1, wherein the distalshaft portion comprises a biaxially oriented thermoplastic polymericmaterial.
 30. The catheter according to claim 1, wherein the distalsection of the hypotube has a bare exposed outer surface and the distalshaft portion is directly bonded to the bare exposed outer surface ofthe hypotube along a portion of the length of the hypotube.
 31. A methodof making a catheter comprising: providing a hypotube having a proximalsection and a distal section with an inflation lumen and a longitudinalaxis defined therethrough, the distal section having a skive defined bya first angled cut, an axial cut, and a second angled cut, wherein thefirst angled cut extends at a first angle relative the longitudinal axisthat is not perpendicular thereto, the second angled cut extends at asecond angle relative the longitudinal axis that is not perpendicularthereto, the axial cut is substantially parallel to the longitudinalaxis, the first angled cut extends to a distal end of the hypotube, andthe distal end of the hypotube comprises a blunt end; forming a distalshaft portion including a guidewire lumen and an inflation lumen definedtherethrough, the inflation lumen of the distal shaft portion configuredto receive at least a portion of the distal section of the hypotube;inserting the distal section of the hypotube within the distal shaftportion with at least the axial cut of the skive engaging the inflationlumen of the distal shaft portion and the inflation lumen of the distalshaft portion in fluid communication with the inflation lumen of thehypotube; and bonding the distal shaft portion to an outer surface ofthe hypotube.
 32. The method of claim 31, wherein forming the distalshaft portion comprises creating a proximal port in a wall of the distalshaft portion, coupling the inner tubular member to the distal shaftportion at the proximal port within an interior of the distal shaftportion, positioning a crescent shaped mandrel in the distal shaftportion adjacent the inner tubular member, and heating the distal shaftportion.
 33. The method of claim 31, wherein the outer surface of thehypotube is roughened prior to bonding of the distal shaft portionthereto.
 34. The method of claim 31, wherein forming the distal shaftportion comprises directly bonding the distal shaft portion to a bareexposed outer surface of the distal section of the hypotube along aportion of the length of the hypotube.